Semiconductor grade PTFE composite pelletizing equipment and pelletizing process

Abstract

The application provides a kind of semiconductor grade PTFE composite pellet granulation equipment and granulation process, belong to high polymer material processing technical field. Wherein, semiconductor grade PTFE composite pellet granulation equipment includes double screw extruder and the cooling water tank being arranged in the discharge port side of double screw extruder, the top of cooling water tank is installed with isolation cylinder, cutting box is fixedly installed in cooling water tank, water inlet pipe is fixedly installed in the bottom of cutting box, discharge pipe is fixedly installed on cutting box, the end of discharge pipe away from cutting box extends to the outside of cooling water tank, and cutting knife is arranged in cutting box. The semiconductor grade PTFE composite pellet granulation equipment provided by the application has the advantages of improving pellet cleanliness and structural stability, improving processing precision and reducing waste rate, and being easy to maintain.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer material processing, and particularly relates to a semiconductor-grade PTFE composite pellet granulation device and a granulation process. BACKGROUND

[0002] The semiconductor-grade PTFE composite pellet is a granular material made of polytetrafluoroethylene (PTFE) as a matrix, through accurate compounding of nanoscale functional fillers (such as graphene, boron nitride, high-purity ceramic powder, etc.), and an ultra-clean granulation process. Its core characteristics revolve around the stringent requirements of semiconductor manufacturing. On the one hand, it needs to meet the ultra-high purity standard; on the other hand, it needs to break through the performance limitations of pure PTFE through compounding modification, such as adding graphene to improve thermal conductivity, adding ceramic powder to enhance anti-creep performance, etc. To meet the above requirements, the existing granulation process usually follows the core process of "raw material plasticization - strip material forming - cooling and shaping - cutting". The PTFE matrix and functional fillers, additives and other raw materials are forced to mix and plasticize by a double-screw extruder, and are extruded into continuous strip material, which is then cooled and cut according to the cleanliness requirements.

[0003] However, the existing granulation equipment still has the following deficiencies in ensuring the cleanliness and structural stability of the pellets: first, during the extrusion and transportation of the strip material to the cutting equipment, only low-temperature inert gas is used for local pre-cooling of the strip material, and there is a lack of isolation and protection devices, which makes it easy for small dust and suspended particles in the air to penetrate the strip material. At this time, the surface temperature of the strip material is relatively high and has a certain viscosity, which easily adsorbs these small contaminants, resulting in excessive impurity content in the final pellets; second, the existing cooling method lacks a "gradient cooling" design, which easily causes the strip material to be suddenly cooled, thereby causing the material body to crack, the surface to wrinkle or irregularly deform, which not only affects the subsequent cutting precision, but also reduces the structural stability of the pellets.

[0004] Therefore, it is necessary to provide a semiconductor-grade PTFE composite pellet granulation device and a granulation process to solve the above technical problems. SUMMARY

[0005] The technical problem solved by the present application is to provide a semiconductor-grade PTFE composite pellet granulation device and a granulation process that can improve the cleanliness and structural stability of the pellets, improve the processing precision, reduce the waste and defective product rate, and be easy to maintain.

[0006] To solve the above-mentioned technical problems, the present invention provides a semiconductor-grade PTFE composite granulation equipment, comprising a twin-screw extruder and a cooling water tank disposed on one side of the discharge port of the twin-screw extruder. An isolation cylinder is installed on the top of the cooling water tank, a pelletizing box is fixedly installed inside the cooling water tank, a water inlet pipe is fixedly installed at the bottom of the pelletizing box, and a discharge pipe is fixedly installed on the pelletizing box. The end of the discharge pipe away from the pelletizing box extends outside the cooling water tank. A U-shaped frame is fixedly installed on the top of the cooling water tank, and a rotating shaft is rotatably mounted on the U-shaped frame. The bottom end of the rotating shaft extends into the pelletizing box and is fixedly mounted with a pelletizing blade. A pelletizing blade is fixedly installed on the top of the U-shaped frame. A first electric motor, the output end of which is fixedly connected to the top of the rotating shaft; a plurality of equally spaced lower positioning cylinders are fixedly installed on the top of the pelletizing box; a fixed plate is fixedly installed inside the isolation cylinder; a plurality of equally spaced upper guide cylinders are fixedly installed on the top of the fixed plate; a plurality of equally spaced air jet rings are installed on the top of the fixed plate, and each air jet ring is coaxial with the corresponding upper guide cylinder and lower positioning cylinder; a gas supply pipe is fixedly installed on the top of the fixed plate, one end of which extends outside the isolation cylinder; a plurality of connecting pipes are fixedly installed on the top of the gas supply pipe, and each of the connecting pipes is connected to a plurality of air jet rings through pipes.

[0007] The jet ring has an annular air passage, and the inner wall of the jet ring has multiple air outlets that are distributed in a rotationally symmetrical manner, and the multiple air outlets are connected to the annular air passage.

[0008] Furthermore, inspection and cleaning ports are provided on both outer walls of the isolation cylinder, and inspection and cleaning plates for sealing the inspection and cleaning ports are fixedly installed on both outer walls of the isolation cylinder.

[0009] Preferably, a plurality of fixed tubes are installed through and rotatably on the fixed plate, and a plurality of jet rings are respectively fixedly installed at the top ends of the plurality of fixed tubes, and the fixed tubes are coaxial with the jet rings. A corrugated hose is fixedly installed at the top end of the connecting tube, and the end of the corrugated hose away from the connecting tube is fixedly connected to the jet ring.

[0010] A gear located below the fixing plate is fixedly sleeved on the outer wall of the fixing tube. A circulating pushing mechanism is installed at the bottom of the fixing plate to cooperate with the gear transmission and drive the fixing tube to reciprocate around its own axis within a preset angle range.

[0011] Preferably, the cyclic driving mechanism includes a moving bar, multiple toothed plates, and a second motor. The moving bar is slidably mounted on the bottom of the fixed plate. The multiple toothed plates are fixedly mounted on the moving bar and mesh with the corresponding gears. The second motor is fixedly mounted on the bottom of the fixed plate. A cam is fixedly mounted on the output end of the second motor. A rotatable connecting rod is rotatably mounted on the end of the moving bar near the second motor. The end of the rotatable connecting rod away from the moving bar is rotatably connected to the cam.

[0012] Preferably, a C-shaped slide rail is fixedly installed at the bottom of the fixed plate, and the moving bar is slidably installed within the C-shaped slide rail.

[0013] Furthermore, locking blocks are fixedly installed on both outer walls of the isolation cylinder, and two sets of locking mechanisms are installed on the top of the U-shaped frame. The two sets of locking mechanisms are respectively engaged with the two locking blocks to achieve locking of the isolation cylinder.

[0014] Preferably, the locking block has an arc-shaped through groove, and the bottom of the locking block is integrally formed with a protrusion. A locking groove is formed on the outer wall of the protrusion away from the isolation cylinder, and the locking groove is connected to the arc-shaped through groove.

[0015] Each of the locking mechanisms includes a fixed base, a limiting rod, a locking block, and a screw. The fixed base is fixedly installed on the top of the U-shaped frame. The limiting rod passes through and is movably installed on the fixed base. One end of the limiting rod away from the fixed base extends into the U-shaped through groove. The locking block is fixedly installed at the bottom of the limiting rod and is located in the locking groove. The screw is threaded onto the top of the fixed base. A slot is provided on the outer wall of the limiting rod. A round pin is integrally formed at the bottom end of the screw, and the bottom end of the round pin extends into the slot.

[0016] Furthermore, a fan-shaped groove is provided on the outer wall of the limiting rod, and a rotating limiting block is fixedly installed on the fixed base. One end of the rotating limiting block extends into the fan-shaped groove and is movably connected to the inner wall of the fan-shaped groove.

[0017] Furthermore, a positioning corner block is fixedly installed on the top of the cooling water tank, and the two inner sidewalls of the positioning corner block are in contact with the two outer sidewalls of the isolation cylinder, respectively.

[0018] To address the above problems, the present invention also provides a granulation process for semiconductor-grade PTFE composite granules, comprising the following steps:

[0019] T1: Mix semiconductor-grade PTFE matrix, functional fillers and additives according to a preset ratio, and place them in a clean and dry environment for pretreatment to remove trace amounts of moisture and impurities from the raw materials and ensure that the cleanliness of the raw materials meets the requirements of semiconductor grade.

[0020] T2: The pretreated composite raw material is fed into the twin-screw extruder. Through the forced mixing and heating plasticizing effect of the twin-screw extruder, the components of the raw material are evenly dispersed. At the same time, the plasticized raw material is extruded into continuous strips and conveyed from the discharge port of the twin-screw extruder to the isolation cylinder.

[0021] T3: After the strip material enters the isolation cylinder, it is guided to the central area of ​​the jet ring by the upper guide cylinder. The external low-temperature nitrogen supply system delivers high-purity low-temperature nitrogen into the jet ring through the gas delivery pipe. The nitrogen is sprayed out through multiple gas outlets of the jet ring, forming a ring-shaped airflow that acts on the surface of the strip material to achieve progressive pre-cooling of the strip material.

[0022] T4: The pre-cooled strip material enters the cooling water tank, is guided by the lower positioning cylinder to maintain a vertical posture and enters the pelletizing box. The first motor is started to drive the pelletizing blade to rotate in the cooling water, cutting the strip material into pellets of the preset size.

[0023] T5: The cut granules are discharged through the discharge pipe to the cooling water tank, then transported to the centrifugal dehydration equipment for dehydration, and then dried to obtain clean and dry semiconductor-grade PTFE composite granules.

[0024] Compared with related technologies, the semiconductor-grade PTFE composite granulation equipment and granulation process provided by the present invention have the following beneficial effects:

[0025] The semiconductor-grade PTFE composite pelletizing equipment provided by this invention, through the setting of the isolation cylinder, can isolate dust and particulate pollutants in the external air, blocking the risk of contamination of the strip material during the pre-cooling stage from the source. On the other hand, the internal components such as the jet ring, gas delivery pipe, and corrugated hose work together to form a low-temperature nitrogen cooling system, which, together with the temperature gradient cooling zone formed by the isolation cylinder, achieves a gradual cooling of the strip material from the extrusion high temperature to the pre-cooling temperature, effectively avoiding the cracking and deformation of the strip material caused by sudden cooling. At the same time, the pre-cooled strip material enters the cooling water tank for further cooling before cutting. The cooling water can remove the heat generated by the friction of the pelletizing blade in real time, preventing PTFE material from sticking to the cutting edge and affecting the cutting accuracy. The closed cavity of the pelletizing box can also prevent the diffusion of PTFE debris generated during the cutting process. With these two protections, the quality of the PTFE composite pellets can be effectively improved.

[0026] The coaxial guiding design of the upper guide cylinder and lower positioning cylinder provides precise guidance for the initial pre-cooling and subsequent water cooling of the strip material. The upper guide cylinder ensures that the freshly extruded flexible strip material accurately enters the center of the jet ring; the lower positioning cylinder can resist the disturbance of the strip material caused by the water flow, further constraining the strip material to maintain a vertical posture when entering the cutting area, avoiding cutting deviation due to material offset. The gas supply pipe is stably connected to an external high-purity low-temperature nitrogen source. The corrugated hose ensures no nitrogen leakage while adapting to the dynamic adjustment requirements of the jet ring. Combined with the dynamic adjustment of the circulation drive mechanism, it drives the jet to reciprocate around the axis of the strip material within a preset angle, so that the nitrogen spray covers the entire circumference of the strip material, ensuring uniform pre-cooling of the strip material, which can significantly reduce the scrap rate caused by material cooling differences.

[0027] The maintenance sealing plates on both sides of the isolation cylinder adopt a convenient disassembly and assembly structure. By opening the sealing plates, core components such as the internal air jet ring and upper guide cylinder can be cleaned or replaced directly. Combined with the setting of the locking mechanism and the locking block, after the limit rod is inserted into the arc through groove in the locking block, the locking block is rotated and locked into the locking groove. Then, the round pin at the bottom of the screw is inserted into the slot on the limit rod to achieve rigid locking of the isolation cylinder. Unlocking is done by reversing the operation, which effectively reduces the debugging time after equipment maintenance and improves the overall operation and maintenance efficiency.

[0028] This invention provides a granulation process for semiconductor-grade PTFE composite granules. This granulation process involves a series of steps, including raw material cleaning pretreatment, gradient pre-cooling and shaping, underwater precision pelletizing, and centrifugal dehydration. This process ensures the high cleanliness and structural stability of semiconductor-grade PTFE composite granules while improving the pellet processing accuracy and production efficiency. It can efficiently prepare PTFE composite granules that meet the stringent requirements of the semiconductor industry. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the semiconductor-grade PTFE composite granulation equipment provided by the present invention;

[0030] Figure 2 for Figure 1 The diagram shows the structure of the cooling water tank.

[0031] Figure 3 for Figure 2 A cross-sectional view of the cooling water tank shown.

[0032] Figure 4 for Figure 3 The diagram shown illustrates the separation of the isolation cylinder from the cooling water tank.

[0033] Figure 5 for Figure 4 A schematic cross-sectional view of the separation cylinder shown;

[0034] Figure 6 for Figure 5 A schematic diagram showing the arrangement of multiple jet rings and multiple upper guide tubes;

[0035] Figure 7 for Figure 6 A structural schematic diagram from another perspective is shown;

[0036] Figure 8 for Figure 7 The diagram shows the connection between the fixed pipe and the jet ring;

[0037] Figure 9 for Figure 8 The top sectional view of the jet ring shown;

[0038] Figure 10 for Figure 7 The diagram shows the assembly of the gear and the gear plate.

[0039] Figure 11 for Figure 3 The diagram shown is a structural schematic of the pelletizing box.

[0040] Figure 12 for Figure 11 A schematic cross-sectional view of the pelletizing box shown;

[0041] Figure 13 for Figure 3 A schematic diagram showing the locking mechanism and the locked block in a separated state;

[0042] Figure 14 for Figure 13 The diagram shows a structural schematic of the locking mechanism from another perspective;

[0043] Figure 15 for Figure 14 The diagram shows the screw and the limiting rod in a separated state.

[0044] Numbering on the map:

[0045] 1. Twin-screw extruder; 2. Cooling water tank; 3. Isolation cylinder; 4. U-shaped frame; 5. First motor; 6. Pelletizing box; 7. Rotating shaft; 8. Pelletizing knife; 9. Water inlet pipe; 10. Discharge pipe; 11. Lower positioning cylinder; 12. Air supply pipe; 13. Fixing plate; 14. Fixing pipe; 15. Air jet ring; 151. Annular air passage; 152. Air outlet; 16. Connecting pipe; 17. Corrugated hose; 18. Upper guide cylinder; 19. Gear; 20. Moving bar; 21. Toothed plate; 22. Second motor; 23. Rotatable connecting rod; 24. Cam; 25. Fixed seat; 26. Limiting rod; 261. Slot; 262. Fan-shaped slide; 27. Locking block; 28. Locking block; 281. Arc through groove; 282. Locking groove; 29. ​​Screw; 30. Rotation limit block; 31. Positioning corner block. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0047] First Embodiment

[0048] Please refer to the following: Figures 1-15In the first embodiment of the present invention, a granulation device for semiconductor-grade PTFE composite granules is proposed, comprising: a twin-screw extruder 1 and a cooling water tank 2 disposed on one side of the discharge port of the twin-screw extruder 1. The twin-screw extruder 1 adopts the conventional design of twin-screw extruders in the prior art, and is used to forcibly mix and heat-plasticize semiconductor-grade PTFE composite raw materials (including PTFE matrix, functional fillers and additives) to ensure uniform dispersion of each component of the raw material, and to extrude the plasticized raw material into continuous strips. The cooling water tank 2 is used to store cooling water to cool the strips in preparation for pelletizing. A water inlet connection pipe is installed on the top of the cooling water tank 2 for connecting to the drain pipe of a centrifugal dewatering machine. An isolation cylinder 3 is installed on the top of the cooling water tank 2. Before entering the cooling water tank 2, the material passes through the isolation cylinder 3. The isolation cylinder 3 serves two purposes: firstly, it isolates the material from external air contaminants such as dust and particles, preventing contamination of the semiconductor-grade PTFE composite strips before subsequent processing; secondly, it contains a low-temperature nitrogen injection component (i.e., the jet ring 15 mentioned below), which provides initial cooling to the passing strips. Simultaneously, the closed structure of the isolation cylinder 3 prevents the rapid diffusion of low-temperature nitrogen into the air, guiding it upwards through the opening at the top. This design creates a gradient cooling zone with gradually decreasing temperature inside the isolation cylinder 3, from the opening to the low-temperature nitrogen injection component, thus providing gradual cooling of the strips and preventing deformation or cracking due to sudden cooling. In case of cracking, a pelletizing box 6 is fixedly installed inside the cooling water tank 2. The pelletizing box 6 is the core cavity for pellet forming and is immersed in cooling water. A water inlet pipe 9 is fixedly installed at the bottom of the pelletizing box 6. A guide hopper is welded onto the pelletizing box 6 to facilitate the smooth discharge of pellets. A discharge pipe 10 is fixedly installed at the discharge end of the guide hopper. The end of the discharge pipe 10 away from the pelletizing box 6 extends to the outside of the cooling water tank 2. The discharge pipe 10 is connected to the inlet of the suction pump on the centrifugal dewatering machine through a pipe. A U-shaped frame 4 is fixedly installed at the top of the cooling water tank 2. A rotating shaft 7 is rotatably installed on the U-shaped frame 4. The bottom end of the rotating shaft 7 extends into the pelletizing box 6 and is fixedly installed with a pelletizing knife 8. The pelletizing knife 8 pelletizes in the water inside the pelletizing box 6 to avoid PTFE material sticking due to frictional heat. The cutting edge and the top of the U-shaped frame 4 are fixedly mounted with a first motor 5. The output end of the first motor 5 is fixedly connected to the top of the rotating shaft 7. The first motor 5 drives the rotating shaft 7 to rotate at high speed, and the rotating shaft 7 drives the pelletizing blade 8 to rotate synchronously. The cutting edge of the pelletizing blade 8 is perpendicular to the conveying direction of the strip material, cutting the continuous strip material into pellets of a preset size. The top of the pelletizing box 6 is fixedly mounted with multiple equally spaced lower positioning cylinders 11. The lower positioning cylinders 11 are located below the surface of the cooling water, guiding the strip material entering the water, effectively preventing the strip material from shifting, bending or shaking under the impact of the water flow, ensuring that the strip material always enters the cutting area in a vertical state. At the same time, the vertical distance between its bottom and the top of the pelletizing blade 8 is maintained between 2-3 mm. This design...This design shortens the path of the strip material from the positioning constraint to the actual cutting, effectively reducing the slight deformation caused by the brief suspension of the strip material. This results in more regular cut particles with smaller length deviations. A fixing plate 13 is fixedly installed inside the isolation cylinder 3. Multiple equally spaced upper guide cylinders 18 are fixedly installed on the top of the fixing plate 13. The inner walls of these guide cylinders are polished (roughness Ra≤0.8μm) to precisely guide the strip material into the center area of ​​the lower jet ring 15. Multiple equally spaced jet rings 15 are installed on the top of the fixing plate 13, and each jet ring 15 is coaxial with its corresponding upper guide cylinder 18 and lower positioning cylinder 11. A gas supply pipe 12 is fixedly installed on the top of the fixing plate 13. One end of the gas supply pipe 12 extends outside the isolation cylinder 3 and connects to an external cryogenic nitrogen supply system. Multiple connecting pipes 16 are fixedly installed on the top of the gas supply pipe 12, and each connecting pipe 16 is connected to a different jet ring 15 via a pipe.

[0049] An annular air passage 151 is provided inside the jet ring 15, and multiple air outlets 152 are provided on the inner wall of the jet ring 15 in a rotationally symmetrical distribution. All the air outlets 152 are connected to the annular air passage 151. High-pressure low-temperature nitrogen gas is evenly distributed from the annular air passage 151 to the multiple air outlets 152 and sprayed out through the multiple air outlets 152, directly acting on the surface of the strip material. Utilizing the low thermal conductivity and rapid heat absorption characteristics of nitrogen gas, the temperature of the strip material is gradually reduced from 200-250℃ after extrusion to 100-120℃. This pre-cooling process can avoid structural stress caused by excessive temperature difference when the strip material directly enters the cooling water tank 2, and effectively prevent defects such as cracking, deformation or surface wrinkles of the strip material.

[0050] In this embodiment, maintenance and cleaning ports are provided on both sides of the outer wall of the isolation cylinder 3. Maintenance sealing plates for sealing the maintenance and cleaning ports are fixedly installed on both sides of the outer wall of the isolation cylinder 3. After removing the maintenance sealing plates, the components on the top of the fixed plate 13 can be cleaned, unclogged, or replaced directly.

[0051] In this embodiment, multiple fixed pipes 14 are rotatably mounted through and on the fixed plate 13. Multiple air jet rings 15 are respectively fixedly mounted on the top ends of the multiple fixed pipes 14, and the fixed pipes 14 and air jet rings 15 are coaxial. A corrugated hose 17 is fixedly mounted on the top end of the connecting pipe 16. The corrugated hose 17 is made of low-temperature resistant fluororubber and has good flexibility and airtightness. The end of the corrugated hose 17 away from the connecting pipe 16 is fixedly connected to the air jet ring 15. The fixed pipe 14 serves as the rotation axis of the air jet ring 15, which can drive the air jet ring 15 to rotate around the axis of the strip material; the corrugated hose 17 ensures the leak-free delivery of nitrogen. Meanwhile, the jet ring 15 can freely expand, contract, or bend as it rotates, avoiding the restriction of the jet ring 15's movement due to the rigidity of the pipe, and ensuring that the cooling process is continuous and uninterrupted. A gear 19 is fixedly sleeved on the outer wall of the fixed pipe 14, located below the fixed plate 13. A circulating push mechanism is installed at the bottom of the fixed plate 13, which is used to drive the fixed pipe 14 to reciprocate around its own axis within a preset angle range. By finely adjusting the jet ring 15, the nitrogen injection angle of the outlet 152 can be dynamically changed, which can cover all areas of the strip material surface and avoid the strip material from being stretched and deformed due to local overheating.

[0052] Preferably, the cyclic driving mechanism includes a moving bar 20, multiple toothed plates 21, and a second motor 22. The moving bar 20 is slidably mounted on the bottom of the fixed plate 13. Specifically, a C-shaped slide rail is fixedly mounted on the bottom of the fixed plate 13, and the moving bar 20 is slidably mounted within the C-shaped slide rail. Multiple toothed plates 21 are fixedly mounted on the moving bar 20 and mesh with corresponding gears 19. The second motor 22 is fixedly mounted on the bottom of the fixed plate 13, and a cam 24 is fixedly mounted on the output end of the second motor 22. A rotatable cam 24 is mounted on the end of the moving bar 20 closest to the second motor 22. The rotatable link 23 is connected to the cam 24 at one end away from the moving bar 20. The second motor 22 drives the cam 24 to rotate at a constant speed. The eccentric structure of the cam 24 causes the eccentric shaft to make circular motion. The rotatable link 23 converts the circular motion of the cam 24 into a pushing and pulling action on the moving bar 20, which drives the moving bar 20 to make reciprocating linear motion along the C-shaped slide rail. The moving bar 20 drives the toothed plate 21 to move back and forth synchronously. The toothed plate 21 drives the fixed tube 14 to reciprocate around its own axis through meshing transmission with the gear 19, and finally realizes the fine adjustment of the angle of the jet ring 15.

[0053] In this embodiment, locking blocks 28 are fixedly installed on both outer walls of the isolation cylinder 3. Two sets of locking mechanisms are installed on the top of the U-shaped frame 4. The two sets of locking mechanisms are respectively engaged with the two locking blocks 28 to lock the isolation cylinder 3. Under normal conditions, the position of the isolation cylinder 3 is locked to ensure that it does not move. When it is necessary to inspect the internal components of the isolation cylinder 3, the locking of the isolation cylinder 3 can be quickly released through simple operation, and then the isolation cylinder 3 can be removed from the top of the cooling water tank 2.

[0054] Specifically, the locking block 28 has an arc-shaped through groove 281 with an arc angle of 270°. A protrusion is integrally formed on the bottom of the locking block 28, and a locking groove 282 is formed on the outer wall of the protrusion on the side away from the isolation cylinder 3. The locking groove 282 communicates with the arc-shaped through groove 281. Each locking mechanism includes a fixed base 25, a limiting rod 26, a locking block 27, and a screw 29. The limiting rod 26 is adapted to the arc-shaped through groove 281. The fixed base 25 is fixedly installed on the top of the U-shaped frame 4. The limiting rod 26 passes through and is movably installed on the fixed base 25. The limiting rod 26 can move laterally on the fixed base 25 and can also rotate axially within a certain angle. The end of the limiting rod 26 away from the fixed base 25 extends into the arc-shaped through groove 281. The locking block 27 is fixedly installed on the limiting rod 26. At the bottom, the locking block 27 is adapted to the locking groove 282. The locking block 27 is located in the locking groove 282. One end of the limiting rod 26 is inserted into the arc groove 281 of the locking block 28. The limiting rod 26 is rotated so that the locking block 27 at the bottom is engaged in the locking groove 282. At this time, the vertical and horizontal displacement of the isolation cylinder 3 is restricted. The screw 29 is threadedly installed on the top of the fixed base 25. The outer wall of the limiting rod 26 has a slot 261. The bottom end of the screw 29 is integrally formed with a round pin. The bottom end of the round pin extends into the slot 261. The screw 29 is turned clockwise so that the round pin at the bottom end of the screw 29 is slowly inserted into the slot 261 of the limiting rod 26. The limiting rod 26 is firmly fixed by the thread preload, so as to prevent the limiting rod 26 from loosening during the operation of the equipment and realize the rigid locking of the isolation cylinder 3.

[0055] In this embodiment, a fan-shaped groove 262 is provided on the outer wall of the limiting rod 26, and a rotating limiting block 30 is fixedly installed on the fixed base 25. One end of the rotating limiting block 30 extends into the fan-shaped groove 262 and is movably connected to the inner wall of the fan-shaped groove 262. Through the cooperation of the fan-shaped groove 262 and the rotating limiting block 30, the limiting rod 26 is restricted to rotating only 90°. When the limiting rod 26 is pulled out of the arc-shaped through groove 281, after holding the handle on the limiting rod 26 and rotating it upwards by 90°, it cannot be rotated further. The locking block 27 rotates with the limiting rod 26 and is in a horizontal state and in the long through opening of the arc-shaped through groove 281. Then, by pulling the limiting rod 26 backwards, the locking block 27 can move in the long through opening, and finally the limiting rod 26 can be pulled out smoothly.

[0056] In this embodiment, a positioning corner block 31 is fixedly installed on the top of the cooling water tank 2. The two inner sidewalls of the positioning corner block 31 are in contact with the outer sidewalls of the two sides of the isolation cylinder 3. The positioning corner block 31 is the "reference coordinate" for the installation of the isolation cylinder 3. When installing the isolation cylinder 3, the horizontal position of the isolation cylinder 3 can be determined by the right angle constraint of the positioning corner block 31, so that the two limiting rods 26 are axially aligned with the two arc through grooves 281 respectively.

[0057] In this embodiment:

[0058] First, the twin-screw extruder 1 is started, and semiconductor-grade PTFE composite raw material is fed into it. The twin-screw extruder 1 uses a conventional twin-screw structure to force-mix and heat-plasticize the raw material, ensuring uniform dispersion of all components. The plasticized raw material is then extruded into continuous strips. These strips first enter the isolation cylinder 3 at the top of the cooling water tank 2. During this process, the upper guide cylinder 18 inside the isolation cylinder 3 precisely guides the strips, ensuring they stably enter the central area of ​​the jet ring 15. Simultaneously, the external low-temperature nitrogen supply system delivers high-pressure low-temperature nitrogen through the gas delivery pipe 12. The nitrogen enters the annular gas passage 151 within the jet ring 15 through the connecting pipe 16 and corrugated hose 17 at the top of the gas delivery pipe 12. From there, it is evenly distributed from the annular gas passage 151 to the rotationally symmetrically distributed gas outlets 152 on the inner wall of the jet ring 15. Finally… The nitrogen gas is applied directly to the surface of the strip material in the form of annular airflow. When the second motor 22 is running, it drives the cam 24 at the output end to rotate at a constant speed. The eccentric structure of the cam 24 drives the moving strip 20 to reciprocate linearly along the C-shaped slide rail through the rotatable connecting rod 23. The toothed plate 21 on the moving strip 20 meshes with the gear 19 on the outer wall of the fixed tube 14, thereby driving the fixed tube 14 and the jet ring 15 at the top to reciprocate within a preset angle around the axis of the strip material, so that the nitrogen injection angle changes dynamically and the strip is pre-cooled. At the same time, the closed structure of the isolation cylinder 3 can reduce nitrogen loss. A gradient cooling zone with gradually decreasing temperature is formed from the top opening to the jet ring 15, thereby gradually cooling the strip. This gradient cooling can avoid the strip material from generating structural stress due to excessive temperature difference, and effectively prevent it from cracking, deforming or having surface wrinkles.

[0059] The pre-cooled strip material continues to be conveyed downwards into the cooling water tank 2, where the water further cools it. It then enters the pelletizing box 6, which is completely immersed in the cooling water of the tank 2. The lower positioning cylinder 11 at the top of the pelletizing box 6 provides secondary guidance to the strip material, ensuring it remains vertical as it enters the cutting area. Subsequently, the first motor 5 at the top of the U-shaped frame 4 starts, driving the rotating shaft 7 to rotate at high speed. The rotating shaft 7 drives the pelletizing blade 8 to rotate synchronously. The cutting edge of the pelletizing blade 8 is perpendicular to the conveying direction of the strip material, cutting the continuous strip material into pellets of a preset size. Because the pelletizing blade 8 operates in the cooling water, frictional heat generation prevents PTFE material from sticking to the cutting edge, further ensuring neat pellet cuts and small dimensional deviations.

[0060] The cut pellets are kept separate by the pelletizing box 6 and will not scatter. When the suction pump on the centrifugal dewatering machine is running, it continuously draws water from the pelletizing box 6. Water from the cooling water tank 2 enters the pelletizing box 6 through the inlet pipe 9, forming a water flow. Under the action of water pressure, the pellets enter the outlet pipe 10 with the water flow and are then transported to the centrifugal dewatering machine for dewatering. At the same time, the water inlet connection pipe at the top of the cooling water tank 2 is connected to the drain pipe of the centrifugal dewatering machine. The cooling water separated during the dewatering process can flow back into the cooling water tank 2, realizing the recycling of cooling water.

[0061] During the overall operation of the equipment, the isolation cylinder 3 is kept stable by the locking blocks 28 on both sides and the locking mechanism at the top of the U-shaped frame 4. The limiting rod 26 is inserted into the arc groove 281 of the locking block 28, and the locking block 27 at the bottom of the limiting rod 26 is engaged in the locking groove 282 on the locking block 28, so as to achieve rigid locking of the isolation cylinder 3 and prevent it from shifting due to equipment vibration. When it is necessary to repair the internal components of the isolation cylinder 3 (such as the air jet ring 15 and the upper guide cylinder 18), the screw 29 is turned in the opposite direction to disengage the round pin from the slot 261. Then, the limiting rod 26 is rotated to make the locking block 27 exit the locking groove 282. The locking can be released by pulling out the limiting rod 26, and the isolation cylinder 3 can be removed from the top of the cooling water tank 2. The operation is convenient.

[0062] Second embodiment:

[0063] In a second embodiment of the present invention, a granulation process for semiconductor-grade PTFE composite granules is provided, comprising the following steps:

[0064] T1: Mix semiconductor-grade PTFE matrix, functional fillers and additives according to a preset ratio, and place them in a clean and dry environment for pretreatment to remove trace amounts of moisture and impurities from the raw materials and ensure that the cleanliness of the raw materials meets the requirements of semiconductor grade.

[0065] T2: The pretreated composite raw material is fed into the twin-screw extruder 1. Through the forced mixing and heating plasticizing effect of the twin-screw extruder 1, the components of the raw material are evenly dispersed. At the same time, the plasticized raw material is extruded into continuous strips and conveyed from the discharge port of the twin-screw extruder 1 to the isolation cylinder 3.

[0066] T3: After the strip material enters the isolation cylinder 3, it is guided by the upper guide cylinder 18 to the central area of ​​the jet ring 15. The external low-temperature nitrogen supply system delivers high-purity low-temperature nitrogen into the jet ring 15 through the gas supply pipe 12. The nitrogen is sprayed out through multiple gas outlets 152 of the jet ring 15, forming a ring airflow that acts on the surface of the strip material to achieve progressive pre-cooling of the strip material.

[0067] T4: The pre-cooled strip material enters the cooling water tank 2, and is guided by the lower positioning cylinder 11 to maintain a vertical posture before entering the pelletizing box 6. The first motor 5 is started to drive the pelletizing knife 8 to rotate in the cooling water, cutting the strip material into pellets of a preset size.

[0068] T5: The cut granules are discharged through the discharge pipe 10 to the cooling water tank 2, and then transported to the centrifugal dehydration equipment for dehydration treatment. After drying, clean and dry semiconductor-grade PTFE composite granules are obtained.

[0069] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A semiconductor-grade PTFE composite pellet granulation apparatus comprising a twin-screw extruder and a cooling water tank provided on one side of a discharge port of the twin-screw extruder, characterized by, The top of the cooling water tank is provided with an isolation cylinder, a pelletizing tank is fixedly installed in the cooling water tank, a water inlet pipe is fixedly installed at the bottom of the pelletizing tank, a discharge pipe is fixedly installed on the pelletizing tank, the end of the discharge pipe away from the pelletizing tank extends out of the cooling water tank, a U-shaped frame is fixedly installed at the top of the cooling water tank, a rotating shaft is rotatably installed on the U-shaped frame, the bottom end of the rotating shaft extends into the pelletizing tank and is fixedly installed with a pelletizing knife, a first motor is fixedly installed at the top of the U-shaped frame, the output end of the first motor is fixedly connected with the top end of the rotating shaft, a plurality of equidistantly arranged lower positioning cylinders are fixedly installed at the top of the pelletizing tank, a fixed plate is fixedly installed in the isolation cylinder, a plurality of equidistantly arranged upper guide cylinders are fixedly installed at the top of the fixed plate, a plurality of equidistantly arranged air jet rings are fixedly installed at the top of the fixed plate, any one of the air jet rings is coaxial with the corresponding upper guide cylinder and lower positioning cylinder, a gas conveying pipe is fixedly installed at the top of the fixed plate, one end of the gas conveying pipe extends out of the isolation cylinder, a plurality of butt pipes are fixedly installed at the top of the gas conveying pipe, and the plurality of butt pipes are respectively connected with the plurality of air jet rings through pipelines. An annular air channel is formed in the air jet ring, and a plurality of air outlets in rotational symmetry are formed in the inner wall of the air jet ring and are in communication with the annular air channel. Locking blocks are fixedly installed on the outer walls of the two sides of the isolation cylinder, two sets of locking mechanisms are installed at the top of the U-shaped frame, and the two sets of locking mechanisms are respectively correspondingly matched with the two locking blocks to lock the isolation cylinder. An arcuate through slot is formed in the locking block, and a protrusion is integrally formed at the bottom of the locking block, a locking slot is formed in the outer wall of the side of the protrusion away from the isolation cylinder, and the locking slot is in communication with the arcuate through slot. Any one of the locking mechanisms comprises a fixing seat, a limiting plug rod, a locking block and a screw rod, the fixing seat is fixedly installed at the top of the U-shaped frame, the limiting plug rod is throughly and movably installed on the fixing seat, the end of the limiting plug rod away from the fixing seat extends into the arcuate through slot, the locking block is fixedly installed at the bottom of the limiting plug rod and is located in the locking slot, the screw rod is threadedly installed at the top of the fixing seat, an insertion slot is formed in the outer wall of the limiting plug rod, and a round insertion pin is integrally formed at the bottom end of the screw rod and extends into the insertion slot. A fan-shaped sliding groove is formed in the outer wall of the limiting plug rod, and a rotating limiting block is fixedly installed on the fixing seat and extends into the fan-shaped sliding groove and is movably connected with the inner wall of the fan-shaped sliding groove.

2. The semiconductor grade PTFE composite pelletization apparatus according to claim 1, wherein, Maintenance and cleaning openings are formed in the outer walls of the two sides of the isolation cylinder, and maintenance sealing plates for sealing the maintenance and cleaning openings are fixedly installed on the outer walls of the two sides of the isolation cylinder.

3. The semiconductor grade PTFE composite pelletization apparatus of claim 1, wherein, A plurality of fixed pipes are installed through and rotatably on the fixed plate, a plurality of the air jet rings are fixedly installed at the top ends of the fixed pipes, and the fixed pipes are coaxial with the air jet rings, a corrugated hose is fixedly installed at the top end of the butt joint pipe, and one end of the corrugated hose away from the butt joint pipe is fixedly connected with the air jet ring; A gear is fixedly sleeved on the outer wall of the fixed pipe and located below the fixed plate, the bottom of the fixed plate is provided with a circulating pushing mechanism for driving the fixed pipe to reciprocatingly rotate around its axis within a preset angle range in transmission cooperation with the gear.

4. The semiconductor grade PTFE composite pelletization apparatus of claim 3, wherein, The circulating pushing mechanism comprises a moving strip, a plurality of toothed plates and a second motor, the moving strip is slidingly installed at the bottom of the fixed plate, the plurality of toothed plates are fixedly installed on the moving strip and engaged with the corresponding gears, the second motor is fixedly installed at the bottom of the fixed plate, a cam is fixedly installed on the output end of the second motor, a rotatable connecting rod is rotatably installed at one end of the moving strip close to the second motor, and the other end of the rotatable connecting rod away from the moving strip is rotatably connected with the cam.

5. The semiconductor grade PTFE composite pelletization apparatus of claim 4, wherein, A C-shaped slide rail is fixedly installed at the bottom of the fixed plate, and the moving strip is slidingly installed in the C-shaped slide rail.

6. The semiconductor grade PTFE composite pelletization apparatus of claim 1, wherein, A positioning angle block is fixedly installed at the top of the cooling water tank, and the two inner side walls of the positioning angle block are respectively in contact with the two side outer walls of the isolation cylinder.

7. A process for pelletizing semiconductor grade PTFE composite pellets using the pelletizing apparatus for semiconductor grade PTFE composite pellets according to any one of claims 1 to 6, characterized by, The method comprises the following steps: T1: mixing semiconductor-grade PTFE matrix, functional fillers and additives according to a preset ratio, pretreating in a clean and dry environment, removing trace water and impurities in the raw materials, and ensuring that the cleanliness of the raw materials meets the requirements of semiconductor grade; T2: feeding the pretreated composite raw materials into a double-screw extruder, uniformly dispersing the components of the raw materials through the forced mixing and temperature rising plasticizing effect of the double-screw extruder, and extruding the plasticized raw materials into a continuous strip, and then conveying the strip from the discharge port of the double-screw extruder to the isolation cylinder; T3: after the strip enters the isolation cylinder, it is guided to the center area of the air jet ring through the upper guide cylinder, the external low-temperature nitrogen supply system conveys high-purity low-temperature nitrogen into the air jet ring through the gas conveying pipe, the nitrogen is sprayed out through the multiple gas outlets of the air jet ring, and the annular gas flow acts on the surface of the strip to realize gradual precooling of the strip; T4: after the pre-cooled strip enters the cooling water tank, it is guided to keep a vertical posture through the lower positioning cylinder and enters the pelletizing box, the first motor is started to drive the pelletizing knife to rotate in the cooling water, and the strip is cut into pellets of a preset size; T5: the cut pellets are guided out of the cooling water tank through the discharge pipe, then conveyed to a centrifugal dewatering device for dewatering treatment, and then dried to obtain clean and dry semiconductor-grade PTFE composite pellets.

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